/// <summary>
/// Returns the signed angle between two vectors.
/// </summary>
/// <param name="v0"></param>
/// <param name="v1"></param>
/// <param name="up"></param>
/// <returns></returns>
public static float SignedAngle(Vector3f v0, Vector3f v1, Vector3f up)
{
var c = Cross(v0, v1);
return(SlurMath.Atan2(c.Length * Math.Sign(Dot(c, up)), Dot(v0, v1)));
}